Heat dissipation device

ABSTRACT

A heat dissipation device ( 100 ) includes a base ( 300 ), a heat sink ( 200 ) and a heat pipe ( 400 ). The base ( 300 ) includes a bottom surface ( 320 ) for thermally contacting with a heat-generating component, a top surface ( 340 ) and two sloped side surfaces ( 360 ) spanning between the top surface ( 340 ) and the bottom surface ( 320 ). The heat sink ( 200 ) includes a plurality of fins perpendicularly attached on the sloped side surfaces ( 360 ) of the base ( 300 ) with a channel defined between the top surface ( 340 ) of the base ( 300 ) and the heat sink ( 200 ). The heat pipe ( 400 ) includes an evaporator ( 420 ) received in the channel defined by the top surface ( 340 ) of the base ( 300 ) and the heat sink ( 200 ) and a condenser ( 440 ) being inserted into the heat sink ( 200 ) above the evaporator ( 420 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat dissipation device, and particularly to a heat dissipation device with minimal resistance to forced airflow.

2. Description of Related Art

In contemporary computers, the most common kind of heat generating component is a central processing unit (CPU). The CPU is the most important controller of electronic signals in a computer. A great heat is generated by CPU during normal operation. This can deteriorate the stability and operation of the CPU. Thus, the heat from the CPU must be removed quickly, to ensure proper operation of the computer. Oftentimes, a heat dissipation device is mounted on a top surface of the CPU to remove heat therefrom.

A conventional heat dissipation device 20 is shown in FIG. 5. The heat dissipation device 20 includes a flat base 22, a plurality of fins 24 extending upwardly from the base 22, and a fan 26 mounted on the fins 24. During operation of the heat dissipation device 20, the fan 26 creates centrifugal outgoing airflow towards the fins 24. When the airflow produced by the fan 26 enters the fins 24, the airflow directly strikes the fins 24, rebounds, and creates obstructing airflow. Additionally, part of the airflow produced by the fan 26 strikes a top surface of the base 22. All this retards airflow from entering the fins 24 and exiting the fins 24, and thus reduces the efficiency of the forced convention between the fins 24 and the airflow produced by the fan 26.

What is needed, therefore, is a heat dissipation device which minimizes resistance to incoming forced airflow and outgoing airflow, and thus enhances heat convection.

SUMMARY OF THE INVENTION

In accordance with an embodiment of the present invention, a heat dissipation device comprises a base, a heat sink and a heat pipe. The base comprises a bottom surface for thermally contacting with a heat-generating component, a top surface and two sloped side surfaces spanning between the top surface and the bottom surface. The heat sink comprises a plurality of fins perpendicularly attached on the sloped side surfaces of the base with a channel defined between the top surface of the base and the heat sink. The heat pipe comprises an evaporator received in the channel defined by the top surface of the base and the heat sink and a condenser being inserted into the heat sink above the evaporator.

Other advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present apparatus can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an assembled view of a heat dissipation device in accordance with a preferred embodiment of the present invention;

FIG. 2 is an exploded view of FIG. 1 with a fan of FIG. 1 being removed away;

FIG. 3 is similar to FIG. 2, but viewed from another aspect;

FIG. 4 is a side elevation view of a heat sink of FIG. 2; and

FIG. 5 is an assembled view of a conventional heat dissipation device in related art.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-4, a heat dissipation device 100 according to a preferred embodiment of the invention is illustrated. The heat dissipation device 100 includes a heat sink 200, a base 300 embedded in a bottom side of the heat sink 200, and two heat pipes 400. Each heat pipe 400 has a U-shaped profile, and includes a flattened evaporator 420 contacting with the base 300, a condenser 440 inserted into the heat sink 200, and a connecting portion 460 connecting the evaporator 420 with the condenser 440. The heat pipes 400 serve to transfer heat from the base 300 to the heat sink 200.

The heat sink 200 comprises a plurality of individual fins arranged side by side. The heat sink 200 can be divided into a top portion 220 and a bottom portion 240.

The top portion 220 has a W-shaped profile, and comprises two platforms 222, a flat crest 224, and two troughs 226. The platforms 222 are formed at opposite sides of the heat sink 200, and serves to supporting a fan 500 thereon. The troughs 226 are defined between the two platforms 222 with the flat crest 224 located between the troughs 226. The flat crest 224 is below the platforms 222 and connected with the platform 222 via the troughs 226. Thus, two plenum chambers are defined beneath the fan 500 by the troughs 226. Two spaced grooves 228 are defined in the flat crest 224 for receiving a clip (not shown) therein, which serves to secure the heat dissipation device 100 on a desired component, such as a printed circuit board (not shown).

Preferably, a rectangular arm portion 229 perpendicularly extends upwardly from an outer edge of each of the platforms 222 to increase the heat exchanging surface of the heat sink 200. The arm portions 229 are located at opposite lateral sides of the fan 500, which is supported on the platforms 222.

The bottom portion 240 of the heat sink 200 has a depression 242 and a rectangular recess 244 defined therein. The recess 244 is located within the depression 242 and extends upward towards the top portion 220 of the heat sink 200. The recess 244 is defined by three walls, namely a top wall 2442 and two side walls 2444 perpendicularly extending downwardly from opposite sides of the top wall 2442.

The depression 242 is defined by two sloped lateral walls 2422 at opposite sides of the recess 244. One of the lateral walls 2422 slants downwardly-outwardly from a bottom edge of one of the sidewalls 2444 and terminates in the bottom side of the heat sink 200. The other one of the lateral walls 2422 slants downwardly-outwardly from a bottom edge of the other sidewall 2444 and terminates in the bottom side of the heat sink 200. In other words, the lateral walls 2422 are inclined toward each other from their bottom ends.

The base 300 is embedded in the depression 242 and has a trapezoidal profile when seen from a front elevation side of FIG. 2. The base 300 has a flat bottom surface 320 in thermal contact with a heat-generating component (not shown), a flat top surface 340, and two sloped side surfaces 360 spanning between the top surface 340 and the bottom surface 320 of the base 300. Each sloped side surface 360 is inclined outwardly away from the top surface 340 along a top-to-down direction.

The sloped side surfaces 360 of the base 300 are attached to the lateral walls 2422 of the depression 242. The size of the top surface 340 of the base 300 is equal to that of the recess 244 but smaller than that of the bottom surface 320 of the base 300.

In assembly of the heat dissipation device 100, the condensers 440 of the heat pipe 400 are inserted into through holes 230 defined in the top portion 220 of the heat sink 200, and the evaporators 420 are received in the recess 244. Preferably, the connecting portions 460 are positioned at opposite sides of the heat sink 200 with a horizontal distance between the evaporators 420 smaller than a horizontal distance between the condensers 440.

Then, the base 300 is disposed in the depression 242 in such a manner that the sloped side surfaces 360 of the base 300 abut against the lateral sidewalls 2422 respectively. Meanwhile, the top surface 340 of the base 300 abuts the bottom edges of the sidewalls 2444 of the recess 244, and a channel is defined by the top wall 2442, the sidewalls 2444 and the top surface 340 of the base 300 for receiving and retaining the evaporators 420 therein. Finally, the fan 500 is positioned on the platforms 222 with the plenum chambers formed beneath the fan 500.

During operation of the heat dissipation device 100, the bottom surface 320 of the base 300 contacts with the heat generating component and absorbs heat therefrom. The heat accumulated at the base 300 then is transferred to the bottom portion 240 of the heat sink 200 via the sloped side surfaces 360 of the base 300 and transferred to the evaporators 420 of the heat pipes 400 via the top surface 340 of the base 300. The heat absorbed by the evaporators 420 can be quickly spread on the top portion 220 of the heat sink 200. Simultaneously, cooling ambient air is drawn into the heat dissipation device 100 via the fan 500. The pressurized air from the fan 500 enters the plenum chambers and then is evenly guided into the spaces between the fins of the heat sink 200 by the troughs 226, and a high velocity airflow is created in the spaces between the fins of the heat sink 200. The air subsequently exits the heat dissipation device 100 along the sloped side surfaces 360 of the base 300 substantially without obstruction. Thus, the heat dissipation device 100 can have a great heat dissipation capability.

It is believed that the present invention and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention. 

1. A heat dissipation device comprising: a base comprising a bottom surface for thermally contacting with a heat-generating component, a top surface and two sloped side surfaces spanning between the top surface and the bottom surface; a heat sink comprising a plurality of fins attached on the sloped side surfaces of the base with a channel defined between the top surface of the base and the heat sink; and a heat pipe comprising an evaporator received in the channel defined by the top surface of the base and the heat sink and a condenser being inserted into the heat sink above the evaporator.
 2. The heat dissipation device as described in claim 1, wherein the top surface of the base is flat.
 3. The heat dissipation device as described in claim 1, wherein the top surface of the base has a size smaller than that of the bottom surface of the base.
 4. The heat dissipation device as described in claim 1, wherein a depression is defined in a bottom portion of the heat sink, and a recess is defined in the bottom portion of the heat sink within the depression, wherein the base is embedded in the depression with the top surface of the base covering the recess to form the channel.
 5. The heat dissipation device as described in claim 4, wherein the recess is defined by a top wall facing the top surface of the base and two sidewalls extending downwardly from opposite sides of the top wall to the top surface of the base.
 6. The heat dissipation device as described in claim 5, wherein the top wall is flat, and the top surface of the base is flat.
 7. The heat dissipation device as described in claim 6, wherein the evaporator of the heat pipe is flat and sandwiched between the top wall and the top surface of the base.
 8. The heat dissipation device as described in claim 5, wherein the depression is defined by two sloped lateral walls at opposite sides of the recess, and the lateral walls each slant downwardly-outwardly from a bottom edge of one of the sidewalls and terminate in a bottom side of the heat sink.
 9. The heat dissipation device as described in claim 1, wherein the heat sink has a W-shaped top portion.
 10. The heat dissipation device as described in claim 9, wherein the top portion of the heat sink comprises two platforms, a crest, and two troughs, wherein the platforms are formed at opposite sides of the top portion of the heat sink, the troughs are defined between the two platforms with the crest located between the troughs.
 11. The heat dissipation device as described in claim 10, further comprising a fan supported on the platforms, and two plenum chambers are defined beneath the fan by the troughs, respectively.
 12. The heat dissipation device as described in claim 11, wherein the heat sink comprises an arm portion extending upwardly from an outer edge of each of the platforms.
 13. The heat dissipation device as described in claim 12, wherein the arm portions clamp at opposite lateral sides of the fan.
 14. A heat dissipation device comprising: a base; a heat sink comprising two platforms formed at opposite sides of a top portion of the heat sink and two troughs symmetrically defined in the top portion of the heat sink between the platforms, the heat sink further comprising two sloped lateral walls symmetrically defined in a bottom portion of the heat sink, wherein the lateral walls are inclined toward each other from their bottom ends, and the heat sink is mounted on the base with the lateral walls attached to the base; and a fan supported on the platforms with two plenum chambers defined beneath the fan by the troughs, respectively.
 15. The heat dissipation device as described in claim 14, wherein the heat sink further comprises an arm portion extending upwardly from an outer edge of each of the platforms, and the arm portions are located at opposite lateral sides of the fan.
 16. The heat dissipation device as described in claim 14, wherein the heat sink further comprises a recess defined in the bottom portion with the sloped lateral walls located at opposite sides of the recess, the recess extends upwardly towards the top portion of the heat sink, wherein the base is embedded in a depression defined by the lateral walls and the base and the recess together define a channel.
 17. The heat dissipation device as described in claim 16, further comprising two heat pipes each having an evaporator received in the channel and a condenser inserted into the top portion of the heat sink.
 18. The heat dissipation device as described in claim 17, wherein the base has a trapeziform cross section with two sloped side surfaces attached to the lateral walls.
 19. A heat dissipation device comprising: a base adapted for attaching to a heat-generating component; a heat sink including a bottom portion and a top portion, the base thermally attached to the bottom portion, the top portion having a W-shaped configuration and including two platforms at opposite sides thereof, a crest at a middle thereof and two troughs each between the crest and a corresponding platform; a fan supported on the platforms of the top portion, two plenum chambers defined under the fan by the troughs, respectively; and at least a heat pipe thermally connecting the base with the top portion of the heat sink.
 20. The heat dissipation device as described in claim 19, wherein the base has a trapeziform cross section with two sloped side surfaces attached to the bottom portion of the heat sink for guiding an airflow generated by the fan. 